1. Field of Invention
The invention relates to a method for correcting skew images, which in particular to an image de-skew technology, acquires the precise skew angle of a scanned image.
2. Related Art
It is familiar to obtain skew images while using a copier to make a copy, or using a scanner to capture images from plane media, such as paper sheets. In general, it is attributed to a medium placed at a skew angle but not at an exact position.
To solve this problem, the key point is how to acquire the precise skew angle. Generally, the characteristics of a scanned image depend on the fundamental elements in a document, such as characters, pictures and tables. Elements available in a document are usually arranged in transverse or lengthwise directions. Most of prior arts obtain the skew angles in accordance with the variations of elements arrangement in transverse or lengthwise directions. However, such methods fail to attain the accurate skew angle due to completely detecting through the whole medium, or every pixel in a predetermined area thereon. Too many variations cause serious interferences while considering all the pixels. Consequently, the calculating result is still an incorrect skew angle, from which another skew image is derived.